Backers can add $5 dollars for a Stemoscope Case or $5 for Strap Kit (45cm&1m).
Here's how to do it:
1. Press the “Manage Your Pledge Button” above.
2. Increase your pledge in the pledge amount box by $5 for each of one or $10 for both.
3. After the end of the Kickstarter campaign, you will receive a survey that asks you questions so that you could tell us which item or services you pledged